Mineral material such as rock is gained from the earth for crushing by exploding or excavating. Rock can also be natural and gravel or construction waste. Mobile crushers and stationary crushers are used in crushing. An excavator or wheeled loader loads the material to be crushed into the crusher's feed hopper from where the material to be crushed may fall in a jaw of a crusher or a feeder moves the rock material towards the crusher. The mineral material to be crushed may also be recyclable material such as concrete, bricks or asphalt.
Mineral crushers typically operate using an electric motor that drives a crusher element through a power transmission system. A typical crusher comprises a body that supports a crushing unit, an electric motor and power transmission, such as a belt and a pair of belt wheels.
FIG. 1a shows an example of a jaw crusher 20. jaw crushers a suitable for example coarse crushing at quarries or for crushing of construction material. According to the function principle of the jaw crusher the crushing takes place against jaws, the so called fixed and movable jaw (a pitman). The body 1 of the jaw crusher is formed of a front end and a rear end and side plates. The fixed jaw 9 is attached to the front end of the jaw crusher which is receiving the crushing forces. The movable jaw 8 is attached to a pitman 4 and the movement of the pitman is generated by rotating an eccentric shaft 5. The jaw crusher comprises additionally a belt wheel 13, V-belts 12, a motor 11 and a belt wheel of the motor for moving the movable jaw 8. Mineral material is crushed between the jaws 8, 9 and is proceeding after the crushing for example via a belt conveyor to further processing.
The jaw crusher 20 comprises further an adjusting apparatus 2 for changing the working angle of the pitman 4 which adjusting apparatus is connected to the pitman via a toggle plate 6. A return rod 7 and a return spring 10 are pulling the pitman towards the adjusting apparatus and at the same time keeping the clearances as small as possible at both ends of the toggle plate.
FIG. 1b shows an example of a track-mounted mobile jaw crushing station 30. The crushing station comprises a body 21 and tracks 22 for moving the crushing plant, a feeder 23 such as a vibrating feeder for feeding material into a jaw crusher 20 and an output conveyor 25 such as a belt conveyor for conveying material for example to the following crushing phase, a motor 11, motor's belt wheel 15, crushing unit's belt wheel 13 and a belt 12. The crushing station comprises also a motor unit 24 comprising for example a diesel motor.
V-belts 12 and belt wheels 13 and 15 are used for coupling the power source to the jaw crusher in prior art. The motor 11 such as a hydraulic or an electric motor is fixed typically to the body of the jaw crusher directly or by a separate motor bed (reference 14 in FIG. 1a) which is a subframe between the body 1 of the jaw crusher and the motor 11. Alternatively the motor is fixed to the body 21 of the crushing station 30 by means of a corresponding subframe 34.
It appears clearly in FIGS. 1a and 1b that the belt-based power transmission and the motor reserve substantial space and increase the size of the crusher. Moreover, to reduce peak strains on the belt, the crushing unit is provided with a flywheel. The belt-based power transmission also requires protective covering around the belt and belt wheels to avoid injuries of the users. The belt-based power transmission also easily excites resonant vibration through the body to associated material conveyors. The resonant vibration causes noise and incurs substantial stress in various structures and therefore heavier and more robust implementation are needed both in the crushing unit itself, in the body of the crusher and in various other structures connected to the crushing unit.
It is an object of the invention to avoid or mitigate problems related to prior known crushers or at least to advance the technology by developing new alternatives to known technologies.